Isolation And Characterization Of Organic Nitrogen Decomposing Bacteria

Organic nitrogen has a wide variety of sources, including nitro compounds,amines, amides, azo compounds, diazole compounds, nitrogen-containingheterocyclic and others. Nitrogen initially exists in the form of organic nitrogen inmost industrial wastewater and domestic sewage. The organic nitrogen graduallytransformed into ammonia in the subsequent processing by the action ofmicroorganisms. Now researchers have in-depth study on high strength ammoniawastewater treatment technologies, but less study on ammonification process.In this study，31strains were isolated from the activated sludge of anoxicreactor.The strain N-1, N-12, N-24and N-28have higher decomposition rate oforganic nitrogen.Based on the morphological characteristics observation andbiochemical properties identification, strain N-1was preliminary identified asSerratiaBizio, strain N-12was preliminary identified as Neisseria, strain N-24andN-28were preliminary identified as Bacillus Cohn.The study investigated the effect of inoculation amount, treatment time,temperature and initial pH on the decomposition process of organic nitrogen. The4strains have higher decomposition rate of organic nitrogen when inoculated bacteriaby30%of inoculation amount.Overmuch inoculation amount could not effectivelyenhance the decomposition rate. N-1and N-12have the highest decomposition rateof organic nitrogen after48h, it were43.38%and45.65%, respectively. N-24andN-28have the highest decomposition rate of organic nitrogen after60h, it were56.16%and48.77%, respectively. All the strain has different temperature toleranceability. The optimum temperature of Strain N-1and N-28was35℃, and StrainN-12and N-24was30℃. In neutral or acidic conditions,4strains have high abilityto decompose organic nitrogen.The12strains, which decomposition rate of organic nitrogen above25%, wereused for compatible experiments. There is obvious synergies and anti-synergy.Through a number of screening experiments, the decomposition rate of part of thecombination remained stable above70%to organic nitrogen.